The invention relates to a sleep apnea detection system and method for detecting apnea and respiratory arrest and more particularly to systems wherein a detector is used in conjunction with an alarm to wake an individual or to summon help to restore a normal an breathing cycle.
Breathing is normally characterized by a regular rhythm of inhaling and exhaling. However, in many individuals apnea or cessation of respiratory airflow causes an interruption in the breathing cycle which can be hazardous to an individual""s health. At times such interruption may result in a complete arrest of breathing.
Apnea may be caused by a number of different mechanisms including obstructive episodes in upper airway, by neurologic or disease-medicated lack of diaphragmatic motion, and by a combination of these factors. Some individuals are particularly vulnerable to apnea after general anesthesia. Others receiving epidural narcotics and local anesthetics are at an increased risk of apnea and respiratory arrest.
A number of monitoring devices, have been proposed. For example, some respiration monitors detect the carbon dioxide level in the air which is exhaled by a patient. Other monitors include oxygen monitors as well as instruments which sense motion of the abdomen. Those instruments which detect the motion of the abdomen generally include elastic strain sensing belts, or infrared motion detectors. Other monitors include acoustic detectors to detect the sound of breathing with specially programmed microphones to determine when cessation of breath or lapses in the breathing rate occur, and thus trigger an alarm.
One approach to a sleep apnea detection system is disclosed in the corn U.S. Pat. No. 6,062,216. As disclosed therein, an apnea monitor includes a detector in a fixed console that directs a beam at a sleep surface. The deflection beam is reflected off a patient and the return light is analyzed to develop a signal which varies with external motion of the patient""s upper body. The motion signals are then fed to a pattern recognizer which identifies breath signals and analyzes them to detect cessation or excessive pauses in breathing and triggers an alarm or intervention to restore breathing regularity.
It is presently believed that there is a need for an improved sleep apnea detection system in accordance with the present invention. Such systems may be used with various detection systems, i.e. respiration monitors, oxygen monitors, acoustic detectors and the like. The system in accordance with the present invention also includes an automatic trigger device, a delay mechanism for avoiding false alarms, a lock-out feature and an automatic reset feature. The systems are also reliable, relatively inexpensive and durable. In addition, such systems are free of sleep inhibiting or disturbing factors and do not require direct contact with a patient.
The apnea monitor and alarm system or device in accordance with the present invention also minimizes the likelihood of a false alarm and allows an individual to interrupt the cycle in order to leave the room and then to automatically reset the program for continued protection.
In essence, the present invention contemplates an apnea monitor and alarm device for monitoring the breathing of an individual and for sounding an alarm in response to an interruption in the individual""s breathing rhythm. The device includes a sensor such as a respiration detector for sensing the cyclical rhythm of the individual""s breathing. The device also includes an alarm and first timing means for establishing a first predetermined period of time during which the cyclical rhythm continues and means for arming the alarm in response to the passage of the first predetermined period of time during which the cyclical rhythm continued. In addition, the device includes means inclusive of the sensor means for detecting an irregularity in the cyclical rhythm of the individual""s breathing. The apnea monitor and alarm device also includes means for establishing a second predetermined period of time during which an interruption in the cyclical rhythm of breathing continues and means for activating the alarm in response to the passage of the predetermined time during which the interruption in the cyclical rhythm of the individual""s breathing continued.
In a preferred embodiment of the invention, an apnea monitor and alarm device includes means for deactivating the alarm and means for automatically reactivating the alarm in response to the passage of the predetermined time during which the cyclical rhythm of breathing continues.